Method for operating a sliding gate, and sliding gate

ABSTRACT

The invention relates to a method for operating a sliding gate for metallurgical vessels in which the sliding gate ( 10 ) has at least two fire-resistant gate plates ( 21, 22 ), which can be tensioned against one another and which are each arranged inside a respective housing part ( 17, 19 ) in a manner that enables them to slide relative to one another. Spring elements ( 23 ) are provided in at least one of the housing parts ( 17, 19 ) in order to tension the gate plates ( 21, 22 ). One gate plate ( 22 ) can, with its housing part ( 19 ), be slid into a closed or open position by means of a drive element. An offline and/or online diagnosis of the operating state is carried out, in particular, in the area of the gate plates ( 21, 22, 41, 42 ) during which one or more variables with regard to dimensions, temperatures, pressures and/or forces are measured at the sliding gate ( 10, 40 ) and are evaluated directly or while including additional relevant process parameters in order to be able to locate it during the operating state and, therefore, during an additional use of the sliding gate ( 10 ). Interruptions can be largely prevented as a result.

The invention concerns a method for the operation of a sliding closurefor metallurgic vessels, whereby the said sliding closure incorporatesat least opposingly tensionable fireproof closure plates which are each,slideably opposingly, positioned along glide surfaces within a housingpart, and whereby spring elements arc envisaged for the tensioning ofthe closure plates in at least one of the housing parts, and whereby oneclosure plate with its housing part can be pushed into a closed, i.e.open position by a drive member.

Sliding closures are utilised especially for the pans or distributioncontainers of extrusion moulding plants for a controlled pouring of thesteel smelt. The fireproof closure plates and fireproof sleeves utilisedfor these sliding closures, through which the liquid steel smelt flows,as well as the mechanism supporting the same are subjected to relativelystrong wear. The plates and sleeves must therefore be replacedfrequently.

In order to achieve a high efficiency these fireproof parts are leftwithin the sliding closure and used as long as possible. It has beendemonstrated by operating personnel how the emptying of pans cansometimes be achieved with the aid of closure plates and sleeves withvisual control and experience. In reality however it has been proventhat breakouts occur due to incorrect estimates or insufficient controlpossibilities, where the steel smelt flows in an uncontrolled mannerthrough the sliding closure and damages or even destroys the same. Thisapplies also to incorrect assemblies of the sliding closure where forexample insufficient mortar has been installed between the fireproofparts.

Based on the aforementioned it is the purpose of this invention toprovide a method for the operation of a sliding closure of the abovementioned type with which operational safety can be increased andpossible imminent operational faults such as breakouts can be recognisedearly.

This task is solved in accordance with the invention by the off- and/oronline diagnosis of the operating condition, especially within the areaof the closure plates, with which one or more dimensions relating tosize, temperature, pressure and/or force of the sliding closure aremeasured and evaluated either directly or together with additionalrelevant process parameters in order to be able to judge the operatingcondition, and therefore also a possible continued use of the slidingclosure.

The method of this invention enables the detection and prevention ofoperational faults and especially breakouts, during which the entiresliding closure mechanics and possibly also parts of the extrusionmoulding plant are often destroyed, as far as possible. Incorrectassemblies of the sliding closure especially can be detected andbreakouts prevented in this way.

With a preferred embodiment the distance of each of the housing partsreceiving the closure plates from one another in a diagonal direction inrelation to the plate glide surfaces is used as a dimension, recorded,and transmitted to an evaluating means, whereby said distance ispreferably measured in several places. The measuring of the distance ofthese two housing parts front one another especially enables thediagnosing of the position of the closure plate with regard to changesin a diagonal direction to the glide surfaces and therefore thedetection of sheets that may form between the plates.

The pressure of the drive member as well as the stroke position of theslideable closure plate are preferably used as the dimension that is tobe measured. i.e. recorded and evaluated, whereby the frictionrelationships and therefore the condition of the closure platesespecially can be deducted from their contacting glide surfaces.

Embodiments of the invention as well as farther advantages of the samewill now be described in more detail with reference to the drawings;whereby:

FIG. 1 shows a schematic illustration of a sliding closure as well as anevaluating means working according to the method of this invention, and

FIG. 2 shows a cross-sectional view of a sliding closure with ameasuring unit.

FIG. 1 shows a schematic illustration of a sliding closure 10 affixed toa metallurgical vessel 15 illustrated only in part, whereby the sameconsists for example of a pan of an extrusion moulding plant containingsteel smelt. As part of the vessel 15 a steel jacket 11, a fireproofcladding 12, a perforated stone 14, as well as a fire-proof sleeve 13with an outlet 16 are shown.

The sliding closure 10 incorporates an upper housing part 17 into whicha fireproof closure plate 21 is affixed. Within a further housing part19 the slideable closure part 22 is held, whereby the housing part 19 isheld within a housing frame 18 and can be moved by a drive member 25into an open position—as illustrated—or into a closed position. Thisdrive member 25 takes the form of a hydraulic piston/cylinder unit andis therefore activated via pipes 26, 27 by a hydraulic aggregate 29. Inaddition the closure plates 21, 22 are pressed against one another byspring elements 23, so that an adequate seal is created between thesame.

According to the invention the method for the operation of the slidingclosure 10 incorporates an off- and/or online diagnosis of the operatingcondition, especially within the area of the closure plates 21, 22,during which several dimensions with regard to size, temperature,pressure and/or force of the sliding closure 10 are measured andevaluated either directly or together with additional relevant processparameters in order to be able to judge the operating condition andtherefore also a possible continued use of the sliding closure 10.

During the evaluation all dimensions measured as actual values arecompared with a target value or a target value range, and a display orsuchlike for the checking or the emergency closure of the slidingclosure is activated if deviations outside of the tolerance limit arefound to exist.

Within the context of the invention the pressure of the drive member aswell as the stroke position of the slideable closure plate is recordedand evaluated as one of the dimensions to be measured, wherebyespecially the friction relationships and therefore the condition of theclosure plates can be judged in this way with the aid of theircontacting glide surfaces. For this purpose the supply lines 26, 27 ofthe cylinder are equipped with pressure sensors 28 which measure theactual pressure and supply corresponding signal values via electriccables 28′ to an evaluating means 20.

During the measuring of the pressure of the drive member conclusionsregarding the friction relationships of the plates 21, 22 depending uponthe stroke position of the sliding plate 22 in relation to the floorplate 21, and also regarding the application pressures of the springelements 23 can be reached. If a deviation from the relevant targetvalue is detected the pouring process can either be discontinued, or thesliding closure can be subjected to a suitable inspection following theconclusion of the pouring process and a necessary replacement of theclosure plates or other defective parts carried out depending on theextent of the deviation. As soon the measured values return to withinthe tolerance value range following the inspection the sliding closurecan be used again.

Further dimensions consist of the temperature measured near the closureplates 21, 22. For this purpose the housing parts 17, 19 are equippedwith measuring sensors 31, 32 at various points, whereby the samemeasure the actual temperatures and transmit the same via relevantelectric cables 33, 34 to the evaluating means 20. These temperaturemeasurements enable the detection of possible leaks where liquid steelcould exit between plate and sleeve, or between the plates, as early aspossible in order to avoid breakouts. As soon as at least one of thesetemperatures deviates from a predetermined value the closure can eitherbe closed immediately or a message can be sent to request an inspectiondepending on the extent of the deviation.

Effectively, the evaluating means 20 incorporates a computer with amonitor 61 and a keyboard 62 for the programming and the menu-drivenadministration of the method. In addition an emergency light 63 and analarm 64 are envisaged, with which possible operational faults of thesliding closure can be audibly, i.e. visually notified. The evaluatingmeans 20 could of course also be connected to an external computer, i.e.a central computer, located for example at a control centre.

In addition, the application pressure of the spring elements 23 thattension the closure plates 21, 22 can be measured in order to determinewhether one or more of the spring elements 23 are no longer functionalSuch a measurement can be carried out with the aid of an expansionmeasurement strip or a piezo element or suchlike.

These pressure measurements as well as the temperature measurements canbe carried out online, i.e. during the pouring process and/or offline,i.e. after the pouring process, when the sliding closure has beenpositioned at an assembly location together with the pall.

The target value or the target value range of the dimensions that are tobe measured with the aid of the additional process parameters can beadjusted during the use of the sliding closure. In this way it is forexample possible that the wear of the glide surfaces i.e. the flowpassages of the closure plates will have an effect on the temperaturesdetected by the measuring sensors 31, 32. In the same way it is possiblethat a temperature increase occurs during the use of the closure withoutany kind of defect being present. These changes are defined as the kindof process parameters which are borne in mind during the evaluation ofthe measured dimensions.

A further characteristic of the method of this invention envisages thata protocolling and a storing of the measured dimensions of the slidingclosure will supply information regarding the pan and the smelt to bepoured with regard to temperature, treatment, pouring time etc. Thesestored dimensions also serve as process parameters to be consideredduring the evaluation, with which the target values are adjusted and afiltering process as part of the comparison of measured dimensions iscarried out with the target values in order to exclude false alarms asfar as possible.

FIG. 2 shows a sliding closure 40 which is described in detail indocument WO-A-00/6325, of which only the details relevant to thisinvention are mentioned below. An upper housing part 47 affixed to avessel 3 5 is envisaged here together with a closure plate 41 that canbe affixed within the same as well as a lower housing part 49, in whicha fireproof closure plate 42 is held, which is moveably arrangedvertical in relation to the drawing plane. Roller guides 44 are locatedon the upper housing part 47, through which the housing par 49 is guidedwithin the same in a moveable way. The spring elements effect themovement of the lower towards the upper closure plate 41, 42 via theseroller guides 44.

Within the context of the invention the housing parts 47, 49 arepreferably equipped with two measuring sensors 50 on both sides, eacharranged at a distance from the other, with which the distance 53 of thetwo housing parts from one another in a diagonal direction with relationto the plate glide surfaces 41′, 42′ is recorded and transmitted to theevaluating means 20 via a relevant cable 51. These measuring sensors 50affixed to tie upper housing part 47 each measure a distance 53 to ameasuring element 52 affixed to the lower housing 49.

These measuring sensors 50 and measuring elements 52 are preferablyencapsulated in a way not described in detail here, so that the same areprotected against damage. They can also be integrated directly into thehousing parts 47, 49. In principle a single measuring sensor 50 wouldalso suffice.

With the measuring of these distances 53, i.e. the linear changes of thetwo housing parts 47, 49 in relation to one another, it is possibleespecially to diagnose the position of the closure plates 41, 42 withregard to diagonal changes in relation to the glide surfaces 41′, 42′.If, for example steel smelt enters between the plates a thin sheet canform there which can press the plates apart and therefore create a riskof an uncontrolled outpouring of steel smelt across the glide surfacesbetween these plates.

The invention has been described sufficiently with reference to theabove embodiments. However, various other embodiments are possible.

In principle the sliding closure could be evaluated with the aid of onlyone of the dimensions described above, i.e. size, temperature, pressureand/or force, preferably in a programme-controlled way.

1. Method for the operation of a sliding closure for metallurgicalvessels, whereby the said sliding closure (10, 40) incorporates at leasttwo opposingly tensionable fireproof closure plates (21, 22, 41, 42)which are each slideably opposingly positioned within a housing part(17, 19, 47, 49), whereby spring elements (23) are incorporated in atleast one of the housing parts (17, 19, 47, 49) for the tensioning ofthe closure plates (21, 22, 41, 42), and whereby one closure plate(22,42) with its housing part (19,49) can be pushed into a closed, i.e.open position by a drive member, characterized in that an off- and/oronline diagnosis of the operating condition, especially within the areaof the closure plates (21,22,41,42) is carried out, during which one ormore dimensions relating to the size, temperature, pressure and/or forceare measured and evaluated for the sliding closure (10, 40) eitherdirectly or together with additional relevant process parameters inorder to be able to judge the operational condition, and therefore alsoa possible continued use of the sliding closure (10, 40).
 2. Methodaccording to claim 1, characterized in that the distance (53) of therelevant housing parts (17, 19, 47, 49) receiving one of the closureplates (21, 22, 41, 42) from one another in the diagonal direction inrelation to the plate glide surfaces is recorded as a dimension andtransmitted to an evaluating means (20), whereby said distance (53) ispreferably measured in several locations.
 3. Method according to claim1, characterized in that the pressure of the drive member (25) as wellas the stroke position of the slideable closure plate (22, 42) arerecorded as a dimension to be measured and evaluated, whereby especiallythe friction relationships and therefore the condition of the closureplates (21, 22, 41, 42) can be judged in this way with the aid of theircontacting glide surfaces (41′, 42′).
 4. Method according to claim 1,characterized in that the temperatures near the housing parts (17, 19,47, 49), the closure plates (21, 22, 41, 42), and/or at other locationsare measured and evaluated.
 5. Method according to claim 1,characterized in that the application pressure of the spring elements(23) that tension the closure plates (21, 22, 41, 42) is measured inorder to determine whether one or more of the spring elements (23) is nolonger functional.
 6. Method according to claim 1, characterized in thatthe dimensions measured as actual values are compared with a targetvalue or a target value range during the evaluation and in that adisplay or suchlike for the checking or the emergency closure of thesliding closure (10, 40) is activated or a continued use of the sameprevented if deviations outside of the tolerance limit are found toexist.
 7. Method according to claim 6, characterized in that the targetvalue or the target value range of the dimensions to be measured isadjusted with the aid of the process parameters during the utilizationperiod of the closure plates (21, 22, 41, 42), whereby the wear upontheir glide surfaces, i.e. their flow passages and/or temperaturechanges are incorporated.
 8. Method according to claim 1, characterizedin that a protocolling and a storing of the measured dimensions of thesliding closure (10, 40), and data relating to the pan and the smelt tobe poured are carried out with regard to temperature, treatment, pouringtime, etc., which are defined as process parameters and incorporatedduring the determination of target values.
 9. Sliding closure,especially for the execution of the method according to claim 1,characterized in that for an off- and/or online diagnosis of theoperating condition one or more measurement sensors or suchlike areincorporated near the housing parts (17, 19, 47, 49), the drive member(25), and/or at other locations especially within the area of theclosure plates (21, 22, 41, 42), with which size, temperature, pressureand/or force can be measured and subsequently evaluated.
 10. Slidingclosure according to claim 9, characterized in, that the housing parts(47, 49) are equipped with at least one measuring sensor (50), i.e. oneassociated measuring element (52), with which a distance (53) of the twohousing parts from one another in a diagonal direction in relation tothe plate glide surfaces (41′, 42′) is evaluated as a dimension and eachtransmitted to the evaluating means (20).